Each corner of the iPad Pro has a speaker driver sitting next to a capped resonance chamber. Each speaker is designed identically, as the iPad Pro shifts the speaker's function depending on the orientation of the device. The two speakers on top provide higher frequencies while the bottom speakers provide lower frequencies.
Once it removed the speaker drivers, the company uncapped the volume chambers, which Apple says gives the iPad Pro's speakers 61 percent more "back volume" than previous iPads. Underneath the carbon fiber caps are enclosures filled with foam, which are used to amplify the speaker's sound.
However, the company notes that the speakers take up a significant amount space that could have been used to increase battery capacity by 50 percent. Previous iPads, due to the lack of premium speakers, were able to dedicate a greater proportion of space to battery capacity. One of the first changes the team noticed was that the logic board has moved to the center of the device, unlike previous iPads where it was off to the side.
Additionally, the logic board's shielding had to be removed before the company was able to remove the logic board itself, unlike previous iPads.
Full article can be found at MacRumors: News and Rumors you care about.